Parksosaurus lived during the Late Cretaceous period from 72–65 million years ago, living up until the extinction of the dinosaurs. Named after its discoverer William Parks, Parksosoaurus was first discovered in 1937, and it was one of the last of its family, living at the end of the Age of Dinosaurs.
Parksosaurus was a small but relatively large dinosaur for its size, roughly around 6–13 feet (2–4 m) long and weighed at 45 kilograms. It had blunt, peg-like teeth, suited to chewing thick leaves and fleshy fruit. Like other hypsilophodonts it had a tail stiffened by bony tendons. Held straight behind it, it's tail helped Parksosaurus keep it's balance.
Like its relatives Dryosaurus, Othnielia, and Leaellynasaura, Parksosaurus lived in large groups for protection. When the group was eating or drinking, one member of the herd was the look out for predators. These small animals also travels with larger animals that could protect them, like Ankylosaurus, Torosaurus, and Triceratops.